Redis原理之网络通信协议笔记

目录

1. RESP协议

​2. 自定义Socket连接Redis

1. RESP协议

 2. 自定义Socket连接Redis

public class MyRedisClient {

static Socket s;

static PrintWriter writer;

static BufferedReader reader;

static Object obj;

public static void main(String[] args) {

try {

// 1.建立连接

String host = "xx";

int port = 6379;

s = new Socket(host, port);

// 2.获取输出流、输入流

writer = new PrintWriter(new OutputStreamWriter(s.getOutputStream(), StandardCharsets.UTF_8));

reader = new BufferedReader(new InputStreamReader(s.getInputStream(), StandardCharsets.UTF_8));

// 3.发出请求

// 3.2.set name helloworld

sendRequest("set", "name", "helloworld");

// 4.解析响应

obj = handleResponse();

System.out.println("obj = " + obj);

// 3.2.set name 虎哥

sendRequest("get", "name");

// 4.解析响应

obj = handleResponse();

System.out.println("obj = " + obj);

} catch (IOException e) {

e.printStackTrace();

} finally {

// 5.释放连接

try {

if (reader != null) reader.close();

if (writer != null) writer.close();

if (s != null) s.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

private static Object handleResponse() throws IOException {

// 读取首字节

int prefix = reader.read();

// 判断数据类型标示

switch (prefix) {

case '+': // 单行字符串，直接读一行

return reader.readLine();

case '-': // 异常，也读一行

throw new RuntimeException(reader.readLine());

case ':': // 数字

return Long.parseLong(reader.readLine());

case '$': // 多行字符串

// 先读长度

int len = Integer.parseInt(reader.readLine());

if (len == -1) {

return null;

}

if (len == 0) {

return "";

}

// 再读数据,读len个字节。我们假设没有特殊字符，所以读一行（简化）

return reader.readLine();

case '*':

return readBulkString();

default:

throw new RuntimeException("错误的数据格式！");

}

}

private static Object readBulkString() throws IOException {

// 获取数组大小

int len = Integer.parseInt(reader.readLine());

if (len <= 0) {

return null;

}

// 定义集合，接收多个元素

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